package tools;

import java.lang.*;
import java.math.*;
/*******************************************************************************
 * 
 * 
 * MD5��ݼ�����
 */

public class MD5_Encoding {

	// RFC1321�ж���ı�׼4*4����ĳ����塣
	static final int S11 = 7,S12 = 12,S13 = 17, S14 = 22;

	static final int S21 = 5,S22 = 9, S23 = 14, S24 = 20;

	static final int S31 = 4,S32 = 11,S33 = 16, S34 = 23;

	static final int S41 = 6,S42 = 10,S43 = 15, S44 = 21;

	// ��RFC1321��׼���岻�ɱ�byte������PADDING
	static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0 };

	// MD5�������е�3�������ݣ�����������ʽ���
	private long[] state = new long[4]; // ����״̬(�ֱ��Ӧa b c d)

	private byte[] buffer = new byte[64]; // ����64���ֽ�˽�л�����
	
	private long[] count = new long[2]; // λ����
	
	// ����һ�μ������16����ASCII�ַ��ʾ�������16���ַ���ʽ��MD5ֵ
	public String resultStr;

	// ����һ�μ������2���������ʾ��һ��16���ֽڣ������128bit��ʽ��MD5ֵ
	public byte[] digest = new byte[16];

	// MD5_Encoding���ṩ����Ҫ�Ľӿں���getMD5ofStr����4������ݼ��ܱ任��������ɶ������ַ���м������㣬�����ַ���ʽ���ؼ��ܽ��
	public String getMD5ofStr(String in) {
		md5Init(); // ��ʼ��
		md5Update(in.getBytes(), in.length());// ����MD5���������
		md5Final(); // �����digest������
		for (int i = 0; i < 16; i++) {
			resultStr += byteToHEX(digest[i]); // ��digest�����е�ÿ��byte�����תΪ16������ʽ���ַ�
		}
		return resultStr;
	}

	// ��׼�Ĺ��캯�����md5Init������г�ʼ������
	public MD5_Encoding() {
		md5Init();
		return;
	}
  
	// md5��ʼ������.��ʼ�����ı�.
	private void md5Init() {
		state[0] = 0x67452301L;  // ����stateΪRFC1321�ж���ı�׼����
		state[1] = 0xefcdab89L;  // ����stateΪRFC1321�ж���ı�׼����
		state[2] = 0x98badcfeL;  // ����stateΪRFC1321�ж���ı�׼����
		state[3] = 0x10325476L;  // ����stateΪRFC1321�ж���ı�׼����
		count[0] = count[1] =0L; // ��ʼ��Ϊ0
		resultStr = "";// ��ʼ��resultStr�ַ�Ϊ��
		for(int i=0;i<16;i++) digest[i]=0;//��ʼ��digest����Ԫ��Ϊ0
		return;
	}

	//����F G H I Ϊ4����� ����Ϊ4����MD5����,���м򵥵�λ����
	private long F(long x, long y, long z) {
		return (x & y) | ((~x) & z);
	}

	private long G(long x, long y, long z) {
		return (x & z) | (y & (~z));
	}

	private long H(long x, long y, long z) {
		return x ^ y ^ z;
	}

	private long I(long x, long y, long z) {
		return y ^ (x | (~z));
	}

	// FF,GG,HH��II����F,G,H,I������н�һ���任
	private long FF(long a, long b, long c, long d, long x, long s, long ac) {
		a += F(b, c, d) + x + ac;
		a = ((int) a << s) | ((int) a >>> (32 - s));  //����long���������ʱʹ���޷�����������>>>
		a += b;
		return a;
	}

	private long GG(long a, long b, long c, long d, long x, long s, long ac) {
		a += G(b, c, d) + x + ac;
		a = ((int) a << s) | ((int) a >>> (32 - s)); //����long���������ʱʹ���޷�����������>>>
		a += b;
		return a;
	}

	private long HH(long a, long b, long c, long d, long x, long s, long ac) {
		a += H(b, c, d) + x + ac;
		a = ((int) a << s) | ((int) a >>> (32 - s));//����long���������ʱʹ���޷�����������>>>
		a += b;
		return a;
	}

	private long II(long a, long b, long c, long d, long x, long s, long ac) {
		a += I(b, c, d) + x + ac;
		a = ((int) a << s) | ((int) a >>> (32 - s));//����long���������ʱʹ���޷�����������>>>
		a += b;
		return a;
	}

	// MD5��������̣�input����Ҫ�任�Ķ������ֽڴ���inputlen�ǳ���
	private void md5Update(byte[] input, int inputLen) {
		int i=0, index, partLen;
		byte[] block = new byte[64];   // ����64���ֽڻ�����
		//���count����indexֵ������long���������ʱʹ���޷�����������>>>
		index = (int) (count[0] >>> 3) & 0x3F; 
		if ((count[0] += (inputLen << 3)) < (inputLen << 3))
			count[1]++;
		count[1] += (inputLen >>> 29);  //����int���������ʱʹ���޷�����������>>>
		partLen = 64 - index;   //����partLenֵ
		if (inputLen >= partLen) {
			md5Memcpy(buffer, input, index, 0, partLen);
			md5Transform(buffer);
			for (i = partLen; i + 63 < inputLen; i += 64) {
				md5Memcpy(block, input, 0, i, 64);
				md5Transform(block);
			}
			index = 0;
		} else
			i = 0;
		md5Memcpy(buffer, input, index, i, inputLen - i);
	}

	// �������д�������ŵ�����digest�С�
	private void md5Final() {

		byte[] bits = new byte[8];
		int index, padLen;
		Encode(bits, count, 8);
		index = (int) (count[0] >>> 3) & 0x3f; //����long���������ʱʹ���޷�����������>>>
		padLen = (index < 56) ? (56 - index) : (120 - index);
		md5Update(PADDING, padLen);
		md5Update(bits, 8);
		Encode(digest, state, 16);
	}

	// byte����Ŀ鿽������input�����е���ʼλ��Ϊinpos������len����ݿ�����output������ʼλ��outpos����
	private void md5Memcpy(byte[] output, byte[] input, int outpos, int inpos,
			int len) {
		int i;
		for (i = 0; i < len; i++)
			output[outpos + i] = input[inpos + i];
	}

	// MD5���ı任���������md5Update������ã�block�Ƿֿ��ԭʼ�ֽ�����
	private void md5Transform(byte block[]) {
		long a = state[0], b = state[1], c = state[2], d = state[3];
		long[] x = new long[16]; 
		Decode(x, block, 64);  
        // ����4����j����
		// ��1��
		a = FF(a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */
		d = FF(d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */
		c = FF(c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */
		b = FF(b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */
		a = FF(a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */
		d = FF(d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */
		c = FF(c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */
		b = FF(b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */
		a = FF(a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */
		d = FF(d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */
		c = FF(c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */
		b = FF(b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */
		a = FF(a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */
		d = FF(d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */
		c = FF(c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */
		b = FF(b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */

		// ��2��
		a = GG(a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */
		d = GG(d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */
		c = GG(c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */
		b = GG(b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */
		a = GG(a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */
		d = GG(d, a, b, c, x[10], S22, 0x2441453L); /* 22 */
		c = GG(c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */
		b = GG(b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */
		a = GG(a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */
		d = GG(d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */
		c = GG(c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */
		b = GG(b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */
		a = GG(a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */
		d = GG(d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */
		c = GG(c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */
		b = GG(b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */

		// ��3��
		a = HH(a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */
		d = HH(d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */
		c = HH(c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */
		b = HH(b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */
		a = HH(a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */
		d = HH(d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */
		c = HH(c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */
		b = HH(b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */
		a = HH(a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */
		d = HH(d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */
		c = HH(c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */
		b = HH(b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */
		a = HH(a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */
		d = HH(d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */
		c = HH(c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */
		b = HH(b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */

		// ��4��
		a = II(a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */
		d = II(d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */
		c = II(c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */
		b = II(b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */
		a = II(a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */
		d = II(d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */
		c = II(c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */
		b = II(b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */
		a = II(a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */
		d = II(d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */
		c = II(c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */
		b = II(b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */
		a = II(a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */
		d = II(d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */
		c = II(c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */
		b = II(b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */
		
		//�ֱ��ۼӵ�state[0],state[1],state[2],state[3]
		state[0] += a;  
		state[1] += b;
		state[2] += c;
		state[3] += d;
	}

	// ��byte�����ת��Ϊ�޷��long�����
	private static long byteToul(byte b) {
		return b >0 ?b : ( b & 0x7F + 128);
	}
 
	// ��byte���͵����ת����ʮ�����ASCII�ַ��ʾ
	private static String byteToHEX(byte in) {
		char[] DigitStr = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
							'A', 'B', 'C', 'D', 'E', 'F' };
		char[] out = new char[2];
		out[0] = DigitStr[(in >> 4) & 0x0F]; //ȡ��4λ
		out[1] = DigitStr[in & 0x0F];        //ȡ��4λ 
		String s = new String(out);
		return s;
	}

	// ��long�����鰴˳����byte������,����Ϊlen
	private void Encode(byte[] output, long[] input, int len) {
		int i, j;
		for (i = 0, j = 0; j < len; i++, j += 4) {
			output[j] = (byte) (input[i] & 0xffL);
			output[j + 1] = (byte) ((input[i] >>> 8) & 0xffL);
			output[j + 2] = (byte) ((input[i] >>> 16) & 0xffL);
			output[j + 3] = (byte) ((input[i] >>> 24) & 0xffL);
		}
	}

	// ��byte�����鰴˳��ϳ�long�����飬����Ϊlen
	private void Decode(long[] output, byte[] input, int len) {
		int i, j;
		for (i = 0, j = 0; j < len; i++, j += 4)
			output[i] = byteToul(input[j]) 
					| (byteToul(input[j + 1]) << 8)
					| (byteToul(input[j + 2]) << 16)
					| (byteToul(input[j + 3]) << 24);
		return;
	}

}
